Azeotropic Distillation Separating HF and HFC-1243zf
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Solution Overview
Problem
The separation of hydrogen fluoride (HF) from fluoroolefins is challenging due to the inefficiency of existing methods like distillation and decantation, which often require large amounts of scrubbing solutions and produce excessive waste.
Innovation Solution
A process involving azeotropic distillation, where a mixture of HF and HFC-1243zf is fed to a distillation column to form an azeotrope, followed by condensation into two liquid phases, allowing for the recycling of either the HF-rich or HFC-1243zf-rich phase, enabling effective separation and purification of both compounds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If aqueous scrubbing is used to separate HF from fluoroolefins, then separation effectiveness is improved, but large amounts of scrubbing solutions are required and excessive waste is produced
Solution Approach 1:
The invention utilizes phase transition of the azeotropic mixture into two liquid phases upon condensation. The distillate containing HF and HFC-1243zf is condensed to form an HF-rich phase and a HFC-1243zf-rich phase, enabling separation without requiring large amounts of scrubbing solutions. This phase transition approach eliminates the waste production associated with aqueous scrubbing while maintaining effective separation.
Solution Approach 2:
HFC-1243zf acts as an intermediary substance that forms an azeotropic mixture with HF. This azeotrope serves as a mediator that facilitates separation through phase transition upon condensation. The intermediary azeotropic composition enables the system to separate HF from fluoroolefins efficiently without the need for excessive scrubbing solutions, thus resolving the contradiction between separation effectiveness and substance loss.
2Reliability
If conventional distillation is used to separate HF from fluoroolefins, then separation is attempted, but the method is very often ineffective due to azeotrope formation
Solution Approach 1:
The invention overcomes the ineffectiveness of conventional distillation by utilizing phase transition upon condensation. Instead of relying solely on volatility differences that are compromised by azeotrope formation, the method condenses the distillate to trigger phase separation into HF-rich and HFC-1243zf-rich liquid phases. This phase transition mechanism enables effective separation despite azeotrope formation during distillation, thereby improving both reliability and productivity.
3Reliability
If decantation is used to separate HF from fluoroolefins, then separation is attempted, but it requires large amounts of scrubbing solutions and produces excessive waste
Solution Approach 1:
The azeotropic composition of HF and HFC-1243zf serves as an intermediary system that enables separation through controlled phase transition. This intermediary approach eliminates the need for large amounts of scrubbing solutions required in traditional decantation methods. The azeotropic mixture naturally separates into two liquid phases upon condensation, achieving effective separation without the substance loss associated with conventional decantation using scrubbing solutions.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method allows for efficient separation and purification of HF and HFC-1243zf, reducing waste and the need for large scrubbing solutions, while achieving high purity levels by leveraging the unique phase behavior of azeotropic compositions.
Implementation Method 1
feeding the composition comprising HF and HFC-1243zf to a first distillation column; removing an azeotrope composition comprising HF and HFC-1243zf as a first distillate
Implementation Method 2
condensing the first distillate to form 2 liquid phases, being i) an HF-rich phase and ii) an HFC-1243zf-rich phase
Data Source
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AI summary
Disclosed herein are processes for the purification of 3,3,3-trifluoropropene or of hydrogen fluoride from mixtures comprising 3,3,3-trifluoropropene and hydrogen fluoride by azeotropic distillation using an entrainer. Also disclosed herein are compositions comprising 3,3,3-trifluoropropene, hydrogen fluoride 1,1,1,2-tetrafluoropropane and/or 1,1,1,3-tetrafluoropropane.